The present invention relates to a package substrate and an electronic device, for example, to a package substrate having a bump and an electronic device having the package substrate.
An arrangement of the bumps of the package substrate mounted over a mounting substrate is decided by a design rule of a diameter of a via formed in the mounting substrate, a diameter of a pad to which the bump in the mounting substrate is electrically coupled, a space of the adjacent vias, a space of the via and wiring, a space of the adjacent via and the pad, a space of the adjacent bumps, etc.
Although miniaturization of the electronic device is demanded in recent years, making a value of the design rule small has a limit technologically. Therefore, it is necessary to design an arrangement of the bumps of the package substrate, the vias and pads of the mounting substrate, and wiring so as to satisfy the demand of the miniaturization of the electronic device within a limit of the design rule. At this time, it is necessary to design so that the arrangement may enable a signal to be outputted to the outside of the mounting substrate from all the pads through extraction wiring and to be inputted from the outside to all the pads.
In a package substrate of U.S. Pat. No. 7,009,115, bumps are arranged in a grid form, and predetermined bumps in the array of bumps being an outermost array are thinned out. Since no pads are arranged in an area of the mounting substrate corresponding to thinned-out bumps, pieces of the extraction wiring are extracted into this void area from the pads arranged in the inside of the mounting substrate. This secures an extraction area of the extraction wiring from the pads arranged in the in side of the mounting substrate.